Indian Oil Corporation (India)

Many microorganisms, especially bacteria, produce biosurfactants when grown on water-immiscible substrates. Biosurfactants are more effective, selective, environmentally friendly, and stable than many synthetic surfactants. Most common biosurfactants are glycolipids in which carbohydrates are attached to a long-chain aliphatic acid, while others, like lipopeptides, lipoproteins, and heteropolysaccharides, are more complex. Rapid and reliable methods for screening and selection of biosurfactant-producing microorganisms and evaluation of their activity have been developed. Genes involved in rhamnolipid synthesis (rhlAB) and regulation (rhlI and rhlR) in Pseudomonas aeruginosa are characterized, and expression of rhlAB in heterologous hosts is discussed. Genes for surfactin production (sfp, srfA, and comA) in Bacillus spp. are also characterized. Fermentative production of biosurfactants depends primarily on the microbial strain, source of carbon and nitrogen, pH, temperature, and concentration of oxygen and metal ions. Addition of water-immiscible substrates to media and nitrogen and iron limitations in the media result in an overproduction of some biosurfactants. Other important advances are the use of water-soluble substrates and agroindustrial wastes for production, development of continuous recovery processes, and production through biotransformation. Commercialization of biosurfactants in the cosmetic, food, health care, pulp- and paper-processing, coal, ceramic, and metal industries has been proposed. However, the most promising applications are cleaning of oil-contaminated tankers, oil spill management, transportation of heavy crude oil, enhanced oil recovery, recovery of crude oil from sludge, and bioremediation of sites contaminated with hydrocarbons, heavy metals, and other pollutants. Perspectives for future research and applications are also discussed.

Production of liquid biofuels, such as bioethanol, has been advocated as a sustainable option to tackle the problems associated with rising crude oil prices, global warming and diminishing petroleum reserves. Second-generation bioethanol is produced from lignocellulosic feedstock by its saccharification, followed by microbial fermentation and product recovery. Agricultural residues generated as wastes during or after processing of agricultural crops are one of such renewable and lignocellulose-rich biomass resources available in huge amounts for bioethanol production. These agricultural residues are converted to bioethanol in several steps which are described here. This review enlightens various steps involved in production of the second-generation bioethanol. Mechanisms and recent advances in pretreatment, cellulases production and second-generation ethanol production processes are described here.

Nonmetal oxidation catalysts have gained much attention in recent years. The reason for this surge in activity is 2-fold: On one hand, a number of such catalysts has become readily accessible; on the other hand, such catalysts are quite resistant toward self-oxidation and compatible under aerobic and aqueous reaction conditions. In this review, we have focused on five nonmetal catalytic systems which have attained prominence in the oxidation field in view of their efficacy and their potential for future development; stoichiometric cases have been mentioned to provide overview and scope. Such nonmetal oxidation catalysts include the alpha-halo carbonyl compounds 1, ketones 2, imines 3, iminium salts 4, and nitroxyl radicals 5. In combination with a suitable oxygen source (H2O2, KHSO5, NaOCl), these catalysts serve as precursors to the corresponding oxidants, namely, the perhydrates I, dioxiranes II, oxaziridines III, oxaziridinium ions IV, and finally oxoammonium ions V. A few of the salient features about these nonmetal, catalytic systems shall be reiterated in this summary. The first class entails the alpha-halo ketones, which catalyze the oxidation of a variety of organic substrates [figure: see text] by hydrogen peroxide as the oxygen source. The perhydrates I, formed in situ by the addition of hydrogen peroxide to the alpha-halo ketones, are quite strong electrophilic oxidants and expectedly transfer an oxygen atom to diverse nucleophilic acceptors. Thus, alpha-halo ketones have been successfully employed for catalytic epoxidation, heteroatom (S, N) oxidation, and arene oxidation. Although high diastereoselectivities have been achieved by these nonmetal catalysts, no enantioselective epoxidation and sulfoxidation have so far been reported. Consequently, it is anticipated that catalytic oxidations by perhydrates hold promise for further development, especially, and should ways be found to transfer the oxygen atom enantioselectively. The second class, namely, the dioxiranes, has been extensively used during the last two decades as a convenient oxidant in organic synthesis. These powerful and versatile oxidizing agents are readily available from the appropriate ketones by their treatment [figure: see text] with potassium monoperoxysulfate. The oxidations may be performed either under stoichiometric or catalytic conditions; the latter mode of operation is featured in this review. In this case, a variety of structurally diverse ketones have been shown to catalyze the dioxirane-mediated epoxidation of alkenes by monoperoxysulfate as the oxygen source. By employing chiral ketones, highly enantioselective (up to 99% ee) epoxidations have been developed, of which the sugar-based ketones are so far the most effective. Reports on catalytic oxidations by dioxiranes other than epoxidations are scarce; nevertheless, fructose-derived ketones have been successfully employed as catalysts for the enantioselective CH oxidation in vic diols to afford the corresponding optically active alpha-hydroxy ketones. To date, no catalytic asymmetric sulfoxidations by dioxiranes appear to have been documented in the literature, an area of catalytic dioxirane chemistry that merits attention. A third class is the imines; their reaction with hydrogen peroxide or monoperoxysulfate affords oxaziridines. These relatively weak electrophilic oxidants only manage to oxidize electron-rich substrates such as enolates, silyl enol ethers, sulfides, selenides, and amines; however, the epoxidation of alkenes has been achieved with activated oxaziridines produced from perfluorinated imines. Most of the oxidations by in-situ-generated oxaziridines have been performed stoichiometrically, with the exception of sulfoxidations. When chiral imines are used as catalysts, optically active sulfoxides are obtained in good ee values, a catalytic asymmetric oxidation by oxaziridines that merits further exploration. The fourth class is made up by the iminium ions, which with monoperoxysulfate lead to the corresponding oxaziridinium ions, structurally similar to the above oxaziridine oxidants except they possess a much more strongly electrophilic oxygen atom due to the positively charged ammonium functionality. Thus, oxaziridinium ions effectively execute besides sulfoxidation and amine oxidation the epoxidation of alkenes under catalytic conditions. As expected, chiral iminium salts catalyze asymmetric epoxidations; however, only moderate enantioselectivities have been obtained so far. Although asymmetric sulfoxidation has been achieved by using stoichiometric amounts of isolated optically active oxaziridinium salts, iminium-ion-catalyzed asymmetric sulf-oxidations have not been reported to date, which offers attractive opportunities for further work. The fifth and final class of nonmetal catalysts concerns the stable nitroxyl-radical derivatives such as TEMPO, which react with the common oxidizing agents (sodium hypochlorite, monoperoxysulfate, peracids) to generate oxoammonium ions. The latter are strong oxidants that chemoselectively and efficiently perform the CH oxidation in alcohols to produce carbonyl compounds rather than engage in the transfer of their oxygen atom to the substrate. Consequently, oxoammonium ions behave quite distinctly compared to the previous four classes of oxidants in that their catalytic activity entails formally a dehydrogenation, one of the few effective nonmetal-based catalytic transformations of alcohols to carbonyl products. Since less than 1 mol% of nitroxyl radical is required to catalyze the alcohol oxidation by the inexpensive sodium hypochlorite as primary oxidant under mild reaction conditions, this catalytic process holds much promise for future practical applications.

Xylanases are hydrolytic enzymes which cleave the β-1, 4 backbone of the complex plant cell wall polysaccharide xylan. Xylan is the major hemicellulosic constituent found in soft and hard food. It is the next most abundant renewable polysaccharide after cellulose. Xylanases and associated debranching enzymes produced by a variety of microorganisms including bacteria, actinomycetes, yeast and fungi bring hydrolysis of hemicelluloses. Despite thorough knowledge of microbial xylanolytic systems, further studies are required to achieve a complete understanding of the mechanism of xylan degradation by xylanases produced by microorganisms and their promising use in pulp biobleaching. Cellulase-free xylanases are important in pulp biobleaching as alternatives to the use of toxic chlorinated compounds because of the environmental hazards and diseases caused by the release of the adsorbable organic halogens. In this review, we have focused on the studies of structural composition of xylan in plants, their classification, sources of xylanases, extremophilic xylanases, modes of fermentation for the production of xylanases, factors affecting xylanase production, statistical approaches such as Plackett Burman, Response Surface Methodology to enhance xylanase production, purification, characterization, molecular cloning and expression. Besides this, review has focused on the microbial enzyme complex involved in the complete breakdown of xylan and the studies on xylanase regulation and their potential industrial applications with special reference to pulp biobleaching, which is directly related to increasing pulp brightness and reduction in environmental pollution.

3D printing by fused deposition modeling (FDM) is an advanced additive manufacturing technology for making thermoplastic-based structures. Several studies have recently investigated 3D printing of polylactic acid (PLA) with biomass resources like cellulose, hemicellulose, lignin and whole biomass. Such biodegradable composites are better for the environment and can be used to replace non-biodegradable composites in a variety of applications. Therefore, a deep understanding of printing such biocomposites is needed for supporting such manufacturing. Recent developments focused on FDM printing of PLA filled with biomass resources have been critically reviewed to reveal the intricate aspects of manufacturing of such materials and characterization of the changes caused by biomass-based fillers. Properties of high molecular weight PLA, essentials of printing with PLA and conditions for filament extrusion and printing of biocomposites are discussed. Characterization results from mechanical testing, thermal analysis, viscoelastic properties, imaging and spectroscopy are reviewed for understanding the impact of filling biomass resources in PLA by printing. The latter sections discuss applications, upcycling & recycling and future opportunities for biorefineries.

The increasing demand for plastics for their widespread applications has ultimately resulted in accumulation of substantial plastic waste, which remains a concern due to limited efforts, inadequacy, and environmental distresses of conventional techniques for waste plastics remediation. The enhanced production of raw materials for polymer syntheses has a dual impact on our ecosystem by causing rapid depletion of nonrenewable petroleum resources and waste generation. To address this situation, researchers have adopted advanced thermochemical recycling processes to produce intermediate products of the petrochemical industries including monomers, fuels, and other value-added products. Such practices can potentially serve the purpose of a circular economy. This review aims to cover the recent highlights in the field of waste plastics pyrolysis including critical observations from the past to provide precise understanding. Consequently, the reactivities and product distributions for plastic feeds, pyrolysis reactors, roles of catalysts, and effects of operating parameters on reactivity and selectivity have been covered. Coprocessing of plastic waste with radioactive materials, biomass, and heavy petroleum residue is also discussed. Furthermore, an overview on kinetics and mechanistic aspects of plastic pyrolysis is presented with a discussion on relevant analytical techniques. The applications of pyrolysis oil as a fuel or fuel additive are comprised in a separate section. Lastly, comparisons of existing chemical recycling technologies, summaries of commercial operations, and future projections are provided.

Abstract The surplus availability of rice straw, its limited usage, and environmental pollution caused by its inefficient burning has fostered research for its valorization to biofuels. This review elucidates the current status of rice straw potential around the globe along with recent advances in revealing the critical factors responsible for its recalcitrance and chemical properties. The role and accumulation of high silica content in rice straw has been elucidated with its impact on enzymatic hydrolysis in a biorefinery environment. The correlation of different pre‐treatment approaches in modifying the physiochemical properties of rice straw and improving the enzymatic accessibility has also been discussed. This study highlights new challenges, resolutions, and opportunities for rice straw based biorefineries. © 2017 Society of Chemical Industry and John Wiley & Sons, Ltd

Abstract Alkyl and aromatic mercaptans are among important organic sulfur compounds distributed in petroleum products. The mercaptans cause foul odor and are corrosive toward metals. In addition, mercaptans may cause oxidative deterioration as well as inhibit the performance of various additives (TEL, antioxidants) in finished products. Therefore, it is necessary to remove them, either by extractive processes or by converting them into innocuous disulfides. Such processes are usually referred to as "sweetening."

The use of ionic liquids as additives to base oil for the lubrication of steel on aluminum was investigated. The miscibility and wear performance of various phosphonium, imidazolium, and pyrrolidinium ionic liquids in a range of polar and nonpolar base oils was determined. The structure and ion pairing of the ionic liquids was found to be important in determining their miscibility in the base oils. In wear tests, some of the miscible base oil/IL blends reduced the aluminum wear depth when compared to that found with the base oil alone. The nonpolar base oil/IL blends were able to withstand higher wear-test loads than the polar base oil/IL blends. At 10 N, as little as 0.01 mol/kg of IL, or 0.7-0.9 wt %, in the nonpolar base oils was enough to drastically reduce the wear depth on the aluminum. XPS analysis of the wear surfaces suggested that the adsorbing of the IL to the surface, where it can form low-shear layers and also react to form tribofilms, is important in reducing friction and wear. The largest reductions in wear at the highest load tested were found for a mineral oil/P6,6,6,14 (i)(C8)2PO2 blend.

Abstract Hydrocracking of vacuum gas oil is an important chemical process involving complex reaction mixtures. The reaction is carried out in a trickle‐bed reactor, considering reaction kinetics along with such hydrodynamic effects as mass transfer, intraparticle diffusion, and partial wetting. Since reaction kinetics is critical to modeling and simulation of a hydrocracking reactor, a modeling approach needs to capture the complex chemistry of the process, along with the elegance of the solution method. The complex chemistry of hydrocarbon is represented by an elegant continuous lumping approach to modeling. The true boiling point of the mixture is used as the characterization parameter. Since the rate constant of hydrocracking is assumed to be a monotonic function of the true boiling point, it is possible to reformulate mass‐balance equations in terms of rate constant as a continuous variable. A novel distribution function p(k, K), which determines the fractional yield distribution of species, was formulated based on data from the cracking patterns of various model compounds. Resulting integrodifferential equations are solved numerically to obtain yields of various fractions as a function of reactor residence time. Model predictions are compared with limited published data to show the utility of the model.

Abstract Isotactic polypropylene was grafted with maleic anhydride using benzoyl peroxide as an initiator and toluene as a solvent. Effects of various parameters such as monomer and initiator concentration, reaction time, and reaction temperature on percentage grafting were studied. Effect of various solvents on extent of grafting was also studied. The maximum extent of grafting achieved was 5.3%. The graft copolymers were characterized by i.r., thermal, viscometric, and contact angle studies. Improved thermal stability and decreased intrinsic viscosity and critical surface tension were observed for graft copolymers. © 1994 John Wiley & Sons, Inc.

Equilibrium adsorption isotherms for methane, ethane, ethylene, acetylene, propane, and propylene have been measured for the first time on mesoporous silica, SBA-15, and the data are analyzed by using the Langmuir−Freundlich adsorption isotherm model. The adsorption capacities for ethylene and propylene are found to be higher than those for corresponding alkanes. Likewise, adsorption of acetylene is more pronounced as compared to ethylene. The isosteric heats of adsorption for various adsorbates estimated by the Clausius−Clapeyron equation are higher for olefins and acetylene and are comparable with those reported for π-complexation based systems. Such a trend has in turn suggested a higher affinity of SBA-15 framework for alkenes over corresponding alkanes, which has been examined in terms of the textural characteristics of SBA-15. It is suggested that SBA-15 can potentially be a good adsorbent for separation of light hydrocarbons.

P-solubilizing bacterial isolate CB7 isolated from apple rhizosphere soil of Himachal Pradesh, India was identified as Bacillus circulans on the basis of phenotypic characteristics, biochemical tests, fatty acid methyl esters analysis, and 16S rRNA gene sequence. The isolate exhibited plant growth-promoting traits of P-solubilization, auxin, 1-aminocyclopropane-1-carboxylate deaminase activity, siderophore, nitrogenase activity, and antagonistic activity against Dematophora necatrix. In vitro studies revealed that P-solubilization and other plant growth-promoting traits were dependent on the presence of glucose in PVK medium and removal of yeast extract had no significant effect on plant growth-promoting traits. Plant growth-promoting traits of isolate CB7 were repressed in the presence of KH2 PO4 . P-solubilization activity was associated with the release of organic acids and a drop in the pH of the Pikovskaya's medium. HPLC analysis detected gluconic and citric acid as major organic acids in the course of P-solubilization. Remarkable increase was observed in seed germination (22.32%), shoot length (15.91%), root length (25.10%), shoot dry weight (52.92%) and root dry weight (31.4%), nitrogen (18.75%), potassium (57.69%), and phosphorus (22.22%) content of shoot biomass over control. These results demonstrate that isolate CB7 has the promising PGPR attributes to be developed as a biofertilizer to enhance soil fertility and promote plant growth.

The present review is focused on a recent development in the preparation of various layered hydrotalcites and their applications in environmental, catalytic and supported materials.

Abstract The recent status of pressure swing adsorption (PSA) as a process for separating multicomponent gas mixtures is reviewed. The applications of a new generation of adsorbents, such as zeolites, carbon molecular sieves, and, more recently, pore engineered molecular sieves, are described in detail. The more important theories of adsorption from gas mixtures as well as those of the PSA process are described briefly. The commercial applications of PSA the process-present and potential-are discussed at length.

Developing highly efficient biocatalyst is a pertinent requirement for biofuels production, in particularly biodiesel/bioethanol. To circumvent the minimal efficiency of conventionally used biocatalysts, nanotechnology paves a way by indulging nanoparticles as carriers of biocatalysts. The nanobiocatalysts so formed are applied as a tool for utilizing wide set of biomass related molecules into biofuels. The disadvantages of conventional biocatalysts such as catalyst deactivation, mass transfer, poisoning, and long reaction time can be outstripped by novel nanobiocatalysts. Nanobiocatalyst increases the catalytic activity; and this higher activity is because of the increased surface to volume ratio and hence it can act as a deoxygenation catalyst too. In recent years, exploiting modern tools for nanoparticles synthesis and characterization yielded high quality optimized and conditioned nanocatalyst systems such as metal oxide nanoparticles, magnetic nanoparticles, and carbon nanotubes to increase the biofuel productivity. Nanomaterial immobilized lipases and cellulases are predictably innovative catalysts having remarkable properties. The present article is critically discussed various nanomaterial immobilized enzyme development and its influence over production of biofuel. Continuous research and development and novel nanobiocatalyst engineering is essential for stabilization of biofuel producing companies.

Abstract Metallocene compounds are becoming an important class of catalyst for the synthesis of organic molecules and polymers [1–6]. These complexes also have good potential to act as catalysts or catalyst precursors for a number of organic reactions [2]. The discovery of Group 4 metallocene-alumoxane systems [7–10] as catalysts for polymerization reactions has opened up a new frontier in the area of organometallic chemistry and polymer synthesis [11–18]. Metallocene systems are comprised of 1) bicomponents consisting of a metallocene and an alumoxane and 2) a single component such as [Cp2MR]+[B(C6F5)4]−. The polymerization of monoolefins by metallocenes in comparison to conventional Ziegler-Natta systems [19–25] offers a versatile possibility to polymer synthesis [26]. The broader flexibility of electronic and steric variations in the cyclopentadienyl (Cp) type ligands allows greater maneuvering in the design of catalyst systems. Such modifications govern the polyinsertion reaction leading to regio- and stereoregular polyolefins. Scientific undestandings in this area have reached a level where full commercial realization is a possibility. Despite all the developmental efforts in the area of metallocene-catalyzed polymerization reactions, no comprehensive review is available on this topic. The scope of this review is restricted to monoolefin polymerizations catalyzed by Group 4 metallocene complexes.

Multiple enzymes are required for efficient saccharification of lignocellulosic biomass and no wild type organism is capable of producing all enzymes in desired levels. In this study, steam explosion of wheat straw was carried out at pilot scale and a synthetic enzyme mixture (EnzMix) was developed by partially replacing the cellulase with critical dosages of commercially available accessory enzymes (β-glucosidase, xylanase and laccase) through central composite design. Highest degree of synergism (DS) was observed with β-glucosidase (1.68) followed by xylanase (1.36). Finally, benchmarking of EnzMix (Celluclast, β-glucosidase and xylanase in a protein ratio of 20.40: 38.43: 41.16, respectively) and other leading commercial enzymes was carried out. Interestingly, saccharification improved by 75% at 6h and 30% at 24h, respectively in comparison of control. By this approach, 25% reduction in enzyme dosage was observed for obtaining the same saccharification yield. Thus development of enzyme cocktail is an effective and sustainable approach for high saccharification efficiency.

The effect of compatibilization on the morphology, mechanical properties, and dynamic mechanical properties of isotactic polypropylene (IPP)/nylon-6 (Ny-6) binary blends was investigated. Maleic anhydride (MAH) functionalized IPP was used as a compatibilizer in binary blends. The morphological, mechanical, and dynamic mechanical properties of binary and ternary blends were compared. The blends containing IPP-g-MAH showed more regular and finer dispersion of phases, different dynamic properties, and improved mechanical properties due to better adhesion between the two phases. The blends were also characterized for their flow properties and extent of water absorption. The melting peak temperature and percent crystallinity of IPP and Ny-6 phases were decreased in compatibilized blends. © 1996 John Wiley & Sons, Inc.

), indole-3-acetic acid (IAA) (8.1μg/mL), siderophores (61.60%), HCN (hydrogen cyanide) production and antifungal activity. We investigated the ability of isolate CKMV1 to solubilize insoluble P via mechanism of organic acid production. High-performance liquid chromatography (HPLC) study showed that isolate CKMV1 produced mainly gluconic (1.34%) and oxalic acids. However, genetic evidences for nitrogen fixation and phosphate solubilization by organic acid production have been reported first time for A. aneurinilyticus strain CKMV1. A unique combination of glucose dehydrogenase (gdh) gene and pyrroloquinoline quinone synthase (pqq) gene, a cofactor of gdh involved in phosphate solubilization has been elucidated. Nitrogenase (nif H) gene for nitrogen fixation was reported from A. aneurinilyticus. It was notable that isolate CKMV1 exhibited highest antifungal against Sclerotium rolfsii (93.58%) followed by Fusarium oxysporum (64.3%), Dematophora necatrix (52.71%), Rhizoctonia solani (91.58%), Alternaria sp. (71.08%) and Phytophthora sp. (71.37%). Remarkable increase was observed in seed germination (27.07%), shoot length (42.33%), root length (52.6%), shoot dry weight (62.01%) and root dry weight (45.7%) along with NPK (0.74, 0.36, 1.82%) content of tomato under net house condition. Isolate CKMV1 possessed traits related to plant growth promotion, therefore, could be a potential candidate for the development of biofertiliser or biocontrol agent and this is the first study to include the Aneurinibacillus as PGPR.